1. Field of the Invention
This invention relates generally to surgically implantable prosthetic devices and, more specifically, to mammary prostheses.
2. Description of Related Art
It has become a practice in the field of surgery to place a prosthetic implant in various areas of the body under any one of various conditions. In cases where cancerous, precancerous, or other abnormal or damaged tissue has been removed, the prosthetic implant is often used as a replacement for the removed tissue and its purpose is to retain the original body contour. An implant of this character provides physical support for the surrounding body tissue, and by filling any voids that are created by the removal of the body tissue preserves the normal outward appearance and feel of the body. Prosthetic devices have also been used to enhance or augment the appearance of body parts.
Breast prostheses have long been used for breast augmentation and for reconstructive surgery following a mastectomy. The prostheses are available in numerous sizes and shapes including teardrop, round, low profile, and high profile. Usually, breast prostheses are implanted via a small inframammary or peri-aerolar incision into a pocket dissected deep to the patient""s own breast tissue in front of the pectoral muscle. In certain situations, the prosthesis may be placed behind the various chest muscles.
Some prosthetic devices have utilized an outer shell or envelope which is filled with a silicone gel, a saline solution, or other liquid, such as an oil or polymer. Other breast prosthetic devices have utilized an envelope which is filled with a combination of silicone gel and saline solution in separate compartments. Prior art silicone gel devices have tactile properties similar to normal tissue, but suffer from certain disadvantages. First, some silicone may bleed through the envelope and migrate into the tissue. Second, rupture of the envelope of a silicone gel implant is difficult for a patient to detect. Third, silicone gel from a ruptured implant may cause an undesirable tissue response.
Some breast prosthetic devices have utilized an outer shell or envelope which is filled with a saline solution. The prior art saline solution filled prosthetic devices suffer from certain disadvantages and lack the proper appearance and tactile properties due to several factors. First, the saline solution displaces too quickly to give the proper tactile properties. Second, the ease of displacement of the saline solution can create a xe2x80x9cfluid wavexe2x80x9d in the implant presenting an unnatural look of the prosthetic device. Third, when the saline solution displaces from one area of the implant, the lack of volume in that area may result in visible wrinkling of the envelope. Fourth, the outer shell or envelope can fold upon itself, causing an area of wear (e.g., fold flaw), leading to failure and deflation.
There are breast prosthetic devices utilizing an outer envelope, wherein the envelope contains baffle forming material. The baffle forming material fills at least a portion of the outer envelope, while the remainder of the outer envelope is filled with a fluid, such as saline solution. The baffle forming material may or may not be attached to the outer envelope. The drawback to such prior art baffle forming material is that such material does not match the single layer structure, geometry, proportions, etc., of the outer envelope, thereby resulting in wrinkling and folding of the implant due to the uncontrolled position of the baffle forming material. Additionally, some of the prior art baffle material can be felt through the implant, resulting in an unnatural feel to the implant.
The object of the present invention is to overcome some of the drawbacks of the prior art implants. It is desirable to construct a surgically implantable prosthetic device which may be filled with saline and/or other fluids and which has the appropriate tactile feel, appearance, and other characteristics found in a human breast. Specifically, the present invention controls the position of the baffle forming material within the lumen with either minimum or no attachment points.
Briefly, according to the present invention, there is provided a surgically implantable prosthetic device, comprising an outer shell having an exterior surface, an interior surface, and enclosing an outer lumen or cavity, wherein the outer lumen is able to accommodate a first fluid therein. The prosthetic device further comprises an inner shell having an exterior surface, an interior surface, and enclosing an inner lumen or cavity, wherein the inner lumen is able to accommodate a second fluid therein. Additionally, the prosthetic device has one or more fitted shells situated between the exterior surface of the inner shell and the interior surface of the outer shell. The fitted shells are adjacent to each other and are arranged in a graduated manner, more specifically, a smaller shell is contained within a successive larger shell.
Both the outer lumen of the outer shell and the inner lumen of the inner shell may be filled with a fluid. The fluid is able to move within the outer lumen and envelop the fitted shells. A saline solution would be an appropriate choice for use as the fluid. Saline refers to any electrolyte combination together with water, however, the invention is not limited solely to the use of saline. Other fluids may be utilized such as, for example, organic polymers or protein fluids; furthermore, certain gases may possibly be utilized as substitutes for fluids. Lubricating agents may be added to the saline.
The prosthetic device utilizing saline or the like provides a safe and harmless prosthetic implant. If the outer shell is ruptured or compromised in any fashion, the saline is safely absorbed into the body tissue. Furthermore, the patient would observe the decrease in volume of the implant and quickly come in for a replacement. This quick indication of implant failure decreases the chance that there would be time for tissue to grow into the implant material after implant rupture due to lack of discovery.
The outer lumen and/or the inner lumen may be pre-filled prior to implantation or, alternatively, may be first implanted and then filled with the fluid. One or more valves may be provided for the filling of the outer lumen, which includes the spaces between the fitted shells, and the inner lumen.
The arrangement of the lumens, the fitted shells, and the inner and outer shells decreases the displacement rate of the fluid. This restriction of the ability of the fluid to move inside the outer lumen improves the desired tactile characteristics of the implant and reduces the xe2x80x9cfluid wavexe2x80x9d effect of the implant. Furthermore, this fitted shell arrangement prevents wrinkling, folding, or bunching together of the baffle material within the implant. Additionally, the outer shell is supported, feels smooth externally, and does not fold upon itself to create wear points.
These and other advantages of the present invention will be understood from the description of the desirable embodiments, taken with the accompanying drawings, wherein like reference numerals represent like elements throughout.